There have been many machines known in the prior art for the manufacture and wrapping of ice cream sandwiches, the basic features of which are well understood by those of ordinary skill in the art. Examples of such prior art devices include those disclosed in U.S. Pat. No. 3,828,660 to Mueller et al., U.S. Pat. No. 3,834,119 to Armitt et al., and U.S. Pat. No. 5,493,957 to Kennedy et al., which are incorporated herein by reference.
As shown in these patents and as is well known in the prior art, an ice-cream sandwich filling machine typically comprises a machine frame to which a series of stations are affixed. The moving components of the machine are typically controlled by a numerical or computer controller through one or more drive mechanisms. The first station is typically the wafer filling station, in which a top and bottom wafer are provided by wafer feeders and an ice-cream extruder discharges ice cream between the wafers. The completed sandwich is then delivered, often via an indexing wheel or similar device, to a conveyor, also affixed to the machine frame, which carries the sandwich toward a wrapping area.
When the sandwich arrives at the wrapping area, it first enters at the bottom of a vertical elevator, where a cut sheet of wrap paper, provided by primary and secondary paper rollers and cut by a rotary knife between the two rollers, is situated atop the sandwich. The paper rollers are typically biased downward through the use of mechanical compression springs to provide friction between the roller and the supplied paper and thus to prevent slippage. The operation of the paper rollers and rotary knife and the arrangement of the cut sheet atop the sandwich is known in the prior art, and typically all of these parts have been commonly driven. The elevator then carries the sandwich and cut sheet upwards through the wrapping assembly, where a pusher mechanism cooperates with side and bottom tucking devices both to fold the paper about the sandwich and to push the wrapped sandwich toward an exit tray. The operation of these tuckers is also known in the prior art. The exit tray in turn includes one or more heated platens, which act to heat seal the bottom overlaps of the cut sheet of wrapping paper to each other, providing a secure wrap.
Despite the periodic improvements reflected in the above-referenced patents, there remain several drawbacks inherent in prior art ice cream sandwich-making machines, particularly with respect to the wrapping of the finished ice-cream sandwich product. For example, in prior art machines, the wrapping station requires either a mechanism to hold the wrapped sandwich during the return stroke of the pusher, or the use of two separate cams to drive separate vertical and horizontal plates. This requires adjustments to the machine and can lead to damage to sandwiches where the hold-back mechanism is employed. In addition, the supply and cutting of the paper to wrap the sandwich in prior art machines suffers from several drawbacks, including the need for improved control of the supply roll through primary and secondary rollers, the need for a sensor to detect when the supply roll is nearly empty, and the need to be able to “park” the paper web to avoid damage to the paper when the machine is stopped. Finally, the exit trays commonly used in prior art machines are usually unbolted from the machine frame in order to gain access below the tray for cleaning operations. This operation is thus time-consuming, resulting in lost filling time. Also, unbolting and removing the exit tray exposes workers to potential harm should the tray, which usually weighs over forty pounds, be dropped.
Further, current ice cream sandwich making machines use a combination of AC motor and gearbox to drive the components of the machine through a series of belts, cams, gearboxes and shafts. This type of drive arrangement is subject to mechanical failure and continuous maintenance. Further, the components of this type of mechanical drive take up substantially more internal space within the machine, congest, interfere, and make difficult the maintenance, repair, and/or replacements of parts or components thereof. In addition, the relative motions and timing of components and stations are normally fixed in current machines, unless the machine is manually adjusted or an existing mechanical set up is changed out typically requiring substantial down time for the machine. Even further, many complex processes, for example motions, phasing and/or timing of components and stations are not achievable with this type of conventional drive arrangement due to limitations of mechanical factors.